Xilinx 7 Series User Manual

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Xilinx 7 Series User Manual Manual pdf 64 page image

64 www.xilinx.com 7 Series FPGAs GTP Transceivers User GuideUG482 (v1.9) December 19, 2016Chapter 2: Shared FeaturesTX and RX Power DownWhen the TX and RX power control signals are used in non PCI Express implementations, TXPDand RXPD can be used independently. Also, when these interfaces are used in non PCI Expressapplications, only two power states are supported, as shown in Table 2-26. When using thispower-down mechanism, these must be true:• TXPD[1] and TXPD[0] are connected together.• RXPD[1] and RXPD[0] are connected together.• TXDETECTRX must be strapped Low.• TXELECIDLE must be strapped to TXPD[1] and TXPD[0].LoopbackFunctional DescriptionLoopback modes are specialized configurations of the transceiver datapath where the traffic streamis folded back to the source. Typically, a specific traffic pattern is transmitted and then compared tocheck for errors. Figure 2-22 illustrates a loopback test configuration with four different loopbackmodes.Loopback test modes fall into two broad categories:• Near-end loopback modes loop transmit data back in the transceiver closest to the trafficgenerator.• Far-end loopback modes loop received data back in the transceiver at the far end of the link.Table 2-26: TX and RX Power States for Operation that are not for PCI ExpressDesignsTXPD[1:0] orRXPD[1:0] Description00 Normal mode. Transceiver TX or RX is active sending or receiving data.11 Power-down mode. Transceiver TX or RX is idle.X-Ref Target - Figure 2-22Figure 2-22: Loopback Testing OverviewTest Logic Near-End GTP1 2 3 4Far-End GTPLink Near-End Test Structures Link Far-End Test StructuresTrafficCheckerTrafficGeneratorRX-PCSRX-PCSTX-PCSTX-PCSTX-PMATX-PMARX-PMARX-PMAUG482_c2_11_111111Send Feedback